Filter

ABSTRACT

A tobacco smoke filter element comprising a solid smoke barrier having a smoke passageway extending between a forward end wall and a sidewall wherein the sidewall is covered with a thin smoke impermeable membrane provided with a plurality of orifices so that the smoke passing through the passageway must escape from the orifices. The several orifices direct the smoke radially from the membrane against an impingement surface which may take the form of a smoke impervious sheet material supported by the barrier plug.

United States Patent [72] Inventor JackieL. White Ptafftown,N.C. 211Appl.No. 24,081 [22] Filed Mar.3l,1970 451 Patented May 11, 1971 [73]Assignee R. J. Reynolds Tobacco Company Winston-Salem, N.C.

541 FILTER 10 Claims, 7 Drawing Figs.

[52] U.S.CI l3l/l0.5, 131/201,131/210,131/212 [51] Int.Cl A24d0l/04,A24f01/08,A24f01/16 [50] FieldofSear-ch 131/10.5,

201,210,261(B),213,218;131/212(A),2l2 I [56] References Cited UNITEDSTATES PATENTS 459,077 9/1891 Lauhoff 131/201X 603,702 5/1898 Nax131/211 1,959,245 5/1934 Levells 131/211X 2,515,547 7/1950 Brawner131/212 2,686,524 8/1954 Kershaw et al. 131/21 1 2,954,787 10/1960Lebert 131/213X 3,312,227 4/1967 Barnett 131/212X 3,318,316 5/1967Banderas et al. 13l/212X 3,496,946 2/1970 Griffith 13 l l 0.5 3,512,5375/1970 Pelletier 131/10.3X FOREIGN PATENTS 20,729 1901 Great Britain131/201 Primary Examiner-Samuel Koren Assistant ExaminerJohn F. PitrelliAttorneyPendleton, Neuman, Williams & Anderson FILTER This inventionrelates to a smoke filter and has for an object the provision of a smokefilter of the multijet impingement type which is particularly suitablefor use in cigarettes, cigars, pipes and other smoking articles.

THE PRIOR ART Smoke filters of the impingement type are well known tothe art. In these devices the smoke, during puffing of the cigarette orother tobacco article, is drawn through one or more small orifices andcaused to impinge at high velocity against a baffle or other impingementsurface whereby the solid and liquid particulate material within thesmoke is deposited on that surface. Certain of the previously proposedfilters have been defic'ient in many respects. Most have a lowefficiency under conditions where the pressure drop is low enough to beacceptable to the average smoker. Also, many of these, particularlythose of the multi orifice type, are of such a structure that they donot lend themselves to production on present-day highspeed cigarettemachines.

FURTHER OBJECTS Accordingly, this invention has for the further objectthe provision of a cigarette filter which is adapted to be produced inconventional high-speed cigarette-making machines of the type nowavailable.

A further object of this invention is the provision of a cigarettefilter of the multijet impingement type which is highly efficient atacceptable pressure drops for removing liquid and particulate materialfrom the cigarette smoke during puffing.

A still further object of this invention is the provision of acombination smoke filter element which is particularly useful in theconstruction of a filter of this invention.

A still further object of the invention is the provision of a multijetimpingement device formed in such a way that careful maintenance oftolerances with respect to the relative position of the variouscomponent parts is avoided.

Further and additional objects will appear from the followingdescription, the accompanying drawing and the appended claims.

GENERAL DESCRIPTION In accordance with one embodiment of this invention,a

combination smoke filter element is provided which includes a solidsmoke barrier plug adapted to be secured to one end of a tobacco rod orother smoking'article. This plug is provided with opposite end walls,one of which is closed and the other of which has an opening. There isalso an opening provided in the sidewall of the plug and a smokepassageway is formed between the two openings. A separate thin membraneof a smoke impervious material is secured to and overlies the sidewallacross the opening therein thereby closing off the smoke passageway.However, this membrane is provided with a plurality of smallsmoke-accelerating orifices whereby substantially all of the smokepassed through the passageway also passes through the orifices. In oneembodiment of the invention, the end of the barrier plug containing theopening is the upstream end so that when smoke is drawn through thecigarette containing the element, the smoke flows through the passagewayin the plug and escapes at a high velocity through the orifices in themembrane in a radially outwardly direction substantially perpendicularto the axis of the plug. When this element is assembled into a cigaretteit is surrounded by a sheet of smoke-impervious material such as tippingpaper which is in spaced relationship to the sheet containing theorifices. Thus, the smoke escaping from the orifices impinges againstthe tipping paper to deposit the wet particulate material, whereafterthe smoke escapes rearwardly to the smokers mouth.

The passageway between the end wall and the sidewall may take the formof a bore, groove or slot, or any combination of these, the importantfeature being that the opening of the passageway adjacent the sidewallbe covered with the orifice containing membrane to provide the desiredorifices for the multijetunit. Usually it is preferred that the barrierplug be cylindrical in shape and that the thin orifice containingmembrane be wrapped around and secured to the external cylindricalsurface of the plug in such a manner that the small orifices communicatewith the smoke passageway in the plug. The plug may be formed of anysuitable plastic material such as polyethylene, polypropylene,polymethylmethacrylate or the like or may be fonned of metal, pressedpaper pulp or any other material that is impermeable to smoke. The thinorifice containing membrane is impermeable to smoke and may be formed ofany suitable plastic, metal foil, treatment paper, and the like, as willbe readily apparent to one skilled in the art.

DESCRIPTION OF THE DRAWINGS For a more complete understanding of thisinvention, reference will now be made to the drawing in which is shownone specific embodiment:

FIG. I is a side elevational view of a smoke barrier plug comprising oneelement of the filter suitable for use in a smoking article inaccordance with this invention;

FIG. 2 is a right-hand end view of the plug shown in FIG. 1;

FIG. 3 is a sectional view taken along the line 3'-3' of FIG.

FIG. 4 is a longitudinal sectional view taken along the line 4-4 of eachof FIGS. 1 and 2;

FIG. 5 is a plan view of a strip of orifice containing sheet materialsuitable for use with the barrier plug shown in FIGS. 1 to 4;

FIG. 6 is a perspective view of the barrier plug of FIGS. 1 to 4 showingthe membrane of FIG. 5 in the process of being assembled on it; and

FIG. 7 is asectional view of the filter end of a cigarette showing thecombination filter element of this invention assembled therein.

SPECIFIC DESCRIPTION Referring first to FIG. 7, the combination smokefilter element of this invention is mounted on the downstream end of aconventional tobacco rod 12 and is spaced forwardly of a conventionalcellulose fiber (e.g., Estron) filter 14. The filter element is securedin assembled relation to rod 12 and the fiber filter 14 by means ofconventional tipping paper 16. The two essential parts of the filterelement of this invention comprise the thin membrane 18 shown in FIG. 5and the barrier plug 20 shown in FIGS. 1 to 4.

The plug 20 constitutes a barrier for the smoke at the downstream end ofthecigarette rod 12. The plug includes a forward or upstream end wall 22and a downstream end wall 24. The upstream end wall is provided with anopening 26 which communicates with a smoke passageway 28 extendingthrough the plug. This plug also has a cylindrical sidewall 30 providedwith a pair of large slots 32 which constitute openings in the sidewallalso in communication with the smoke passageway 28. The forward orupstream end of the plug is cylindrical in nature and provides a supportfor the tipping paper 16 when the cigarette is assembled. The body ofthe plug 20 rearwardly or downstream of the slots 32 is provided with aplurality of integral protuberances 34 which also provide support forthe tipping paper 16. These protuberances 34 are arrangedcircumferentially around the rear section of the plug 20 and definetherebetween downstream passageways for the smoke.

As most clearly shown in FIG. 6, the membrane 18 is wrapped around thereduced cylindrical rearward section 30 of the plug 20 and preferablyadhesively secured thereto or otherwise laminated therewith in such amanner as to seal the slots 32 and hence the smoke passageway 28 exceptfor a plurality of small acceleration orifices 36 which are provided inthe membrane. Thus, in the assembled condition the membrane overlies andconforms and is secured to the outer surface 30 of the rearward portionof the plug 20. The membrane also overlies the slots or openings 32 inthe sidewall. Accordingly, when smoke is puffed in the assembled unit,it passes downstream from the tobacco rod 12 into the passageway 28 andescapes through the orifices 36 into an annular passageway 38 betweenthe tipping paper 16 and the orifice membrane 18. When this occurs, thesmoke is jetted at high velocity against the impingement surface formedby the inner surface of the smoke-impervious tipping paper and the wetparticles contained in the smoke are deposited on that surface. Thesmoke then passes rearwardly or downstream between the protuberances 34through the fiber filter 14 and to the mouth of the smoker. Whiletipping paper is shown as providing the impingement surface for thesmoke, it will be appreciated that it may be fonned of a sleeve of anyother smoke impervious material such as plastic, metal or the like.

It is preferred that the filter element contain at least small orifices18 through which the smoke can pass and it is also preferred that theorifice membrane be not more than about 0.01 inch thick. For bestresults it is further preferred that the distance from the downstreamoutlet of the orifice to the impingement surface should be withincertain specified limits, e.g., between about 0.008 and 0.022 inch. lnthe embodiment shown, this distance is determined by the length of theshoulder 40 between the cylindrical forward end and the reducedcylindrical rearward end of the plug 20 and the thickness of themembrane 18. Thus, it is preferred that the radius of the forwardsection of the plug 20 should be between 0.008 and 0.022 inch greaterthan the radius of the cylindrical rearward section plus the thicknessof the membrane.

It will be appreciated that the plug 20 may be readily formed byconventional injection molding techniques and that the membrane 18 canbe readily secured thereto by a suitable adhesive or otherwise byconventional high-speed machinery. The assembled unit can then beattached to a tobacco rod either with or without the cellulose acetatefilter 14 by conventional methods. In the embodiment shown the tippingpaper constitutes an integral part of the filter after assembly since itprovides the impingement surface. This tipping paper is supported by theenlarged forward cylindrical section of the plug, the protuberances 34and (when used) the cellulose acetate filter 12. The rearward end wall24 does not have an opening which communicates with the passageway 28and the forward end wall 22 and the membrane 18 are positioned so thatall of the smoke drawn from the tobacco rod is required to pass throughthe multijet orifices.

While one specific embodiment of this invention has been described inthe foregoing, it will be appreciated that other modifications may bemade without departing from the spirit and scope of the appended claims.

l'claim:

l. A combination smoke filter element comprising a solid smoke barrierplug having opposite end walls and a sidewall, means in said plugdefining a smoke passageway between an opening in one of said end wallsand an opening in said sidewall, a separate an independent, one-piece,thin membrane of smoke-impervious material immovably secured to andoverlying said sidewall across the opening therein closing off saidsmoke passageway, and means defining a plurality of small smokeacceleration orifices in that portion of said membrane overlying saidsidewall opening whereby substantially all of the smoke passed throughsaid passageway also passes through said orifices.

2. A combination smoke filter element comprising a solid smoke barrierplug having opposite end walls and a substantially cylindrical outersidewall, means in said plug defining a smoke passageway between anopening in one of said end walls and an opening in said sidewall, aseparate and independent, one-piece, thin membrane of smoke-imperviousmaterial immovably secured to and overlying and sealed to said sidewallacross the opening therein closing off said passageway, and meansdefining a plurality of small smoke ac celeration orifices ofsubstantially equal cross section in that portion of said membrane overyrng said sidewall opening whereby substantially all of the smoke passedthrough said passageway also passes through said orifices.

3. A combination smoke filter element comprising a smoke barrier plughaving opposite end walls and a substantially cylindrical outersidewall, means defining a smoke passageway in said plug terminating inopenings in one of said end walls and in said sidewall, a separate andindependent membrane in the shape of a cylinder of a smoke-imperviousmaterial immovably laminated to the surface of said outer sidewallacross the opening therein and closing off said passageway, and meansdefining a plurality of small smoke acceleration orifices in saidmembrane in communication with said passageway whereby all of the smokepassing through said passageway also passes through said orifices.

4. A combination smoke filter element comprising a substantiallycylindrical smoke barrier plug including a rearward section and aforward section having a forward end wall, each of said sections beingcoaxial and having a substantially cylindrical outer sidewall, theforward section being of greater diameter than the rearward section,means extending through said sections defining a smoke passagewaythrough said plug between an opening in said forward end wall and anopening in the sidewall of said rearward section, a separate thinflexible membrane of smoke-impervious material immovably overlying theopening in the sidewall of said rearward section closing off saidpassageway, and means defining a plurality of smoke accelerationorifices of substantially equal cross section in said membrane incommunication with said passageway whereby substantially all of thesmoke passed through said passageway also passes through said orifices.

5. The element recited in claim 4 wherein the thickness of said membraneis less than about 0.01 inch and the radius of the cylindrical forwardsection is between about 0.008 and 0.022 inch greater than the radius ofthe cylindrical rearward section plus the thickness of said membrane.

6. A smoking article including a filter of the multijet impingement typein the downstream end thereof which comprises a smoke barrier plughaving upstream and downstream end walls and a sidewall, means in saidplug including openings in said upstream end wall and said sidewalldefining a first passageway, a separate thin flexible membrane ofsmokeimpervious material immovably overlying said sidewall across saidopening therein closing off said first smoke passageway, means defininga plurality of small smoke acceleration orifices in said membranewhereby substantially all of the smoke passing through said firstpassageway also passes through said orifices in a radially outwardlydirection, means defining an impingement surface spaced radiallyoutwardly from said orifices against which smoke impinges duringsmoking, and means defining a second smoke passageway downstream of saidimpingement surface through which smoke is withdrawn from the filterduring smoking.

7. The smoking article recited in claim 6 wherein the plug is generallycylindrical and the membrane is also in the form of a cylinder laminatedto said sidewall over the opening therein.

8. The smoking article recited in claim 6 wherein the thickness of themembrane is less than about 0.0l inch and the distance between each ofthe orifices and the impingement surface is between about 0.008 and0.022 inch.

9. The smoking article recited in claim 6 wherein the plug includes agenerally cylindrical forward section and a generally cylindricalrearward section of less radius than the former, wherein the smokepassageway terminates in an opening in the sidewall of the rearwardsection, and wherein a separate smoke-impervious sheet supported by theforward section provides said impingement surface.

10. The smoking article recited in claim 9 wherein the rearward sectionincludes radially outwardly extending protuberances spaced rearwardly ofsaid orifices for further supporting the sheet providing the impingementsurface.

Patent No. 3,577,995 Dated May 11, 1971 Inventor(s) Jackie t It iscertified and that said Letters that error appears in theabove-identified patent Patent are hereby corrected as shown below:

Column 2, line 13,

"treatment" should read treated Column 3, claim I, line 57,

change "an" to and Signed and sealed this 1 7th day of August 1 971(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Gfi'icerCommissioner of Patents

1. A combination smoke filter element comprising a solid smoke barrierplug having opposite end walls and a sidewall, means in said plugdefining a smoke passageway between an opening in one of said end wallsand an opening in said sidewall, a separate an independent, one-piece,thin membrane of smoke-impervious material immovably secured to andoverlying said sidewall across the opening therein closing off saidsmoke passageway, and means defining a plurality of small smokeacceleration orifices in that portion of said membrane overlying saidsidewall opening whereby substantially all of the smoke passed throughsaid passageway also passes through said orifices.
 2. A combinationsmoke filter element comprising a solid smoke barrier plug havingopposite end walls and a substantially cylindrical outer sidewall, meansin said plug defining a smoke passageway between an opening in one ofsaid end walls and an opening in said sidewall, a separate andindependent, one-piece, thin membrane of smoke-impervious materialimmovably secured to and overlying and sealed to said sidewall acrossthe opening therein closing off said passageway, and means defining aplurality of small smoke acceleration orifices of substantially equalcross section in that portion of said membrane overlying said sidewallopening whereby substantially all of the smoke passed through saidpassageway also passes through said orifices.
 3. A combination smokefilter element comprising a smoke barrier plug having opposite end wallsand a substantially cylindrical outer sidewall, means defining a smokepassageway in said plug terminating in openings in one of said end wallsand in said sidewall, a separate and independent membrane in the shapeof a cylinder of a smoke-impervious material immovably laminated to thesurface of said outer sidewall across the opening therein and closingoff said passageway, and means defining a plurality of small smokeacceleration orifices in said membrane in communication with saidpassageway whereby all of the smoke passing through said passageway alsopasses through said orifices.
 4. A combination smoke filter elementcomprising a substantially cylindrical smoke barrier plug including arearward section and a forward section having a forward end wall, eachof said sections being coaxial and having a substantially cylindricalouter sidewall, the forward section being of greater diameter than therearward section, means extending through said sections defining a smokepassageway through said plug between an opening in said forward end walland an opening in the sidewall of said rearward section, a separate thinflexible membrane of smoke-impervious material immovably overlying theopening in the sidewall of said rearward section closing off saidpassageway, and means defining a plurality of smoke accelerationorifices of substantially equal cross section in said membrane incommunication with said passageway whereby substantially all of thesmoke passed through said passageway also passes through said orifices.5. The element recited in claim 4 wherein the thickness of said membraneis less than about 0.01 inch and the radius of the cylindrical forwardsection is between about 0.008 and 0.022 inch greater than the radius ofthe cylindrical rearward section plus the thickness of said membrane. 6.A smoking article including a filter of the multijet impingement type inthe downstream end thereof which comprises a smoke barrier plug havingupstream and downstream end walls and a sidewall, means in said plugincluding openings in said upstream end wall and said sidewall defininga first passageway, a separate thin flexible membrane ofsmoke-impervious material immovably overlying said sidewall across saidopening therein closing off said first smoke passageway, means defininga plurality of small smoke acceleration orifices in said membranewhereby substantially all of the smoke passing through said firstpassageway Also passes through said orifices in a radially outwardlydirection, means defining an impingement surface spaced radiallyoutwardly from said orifices against which smoke impinges duringsmoking, and means defining a second smoke passageway downstream of saidimpingement surface through which smoke is withdrawn from the filterduring smoking.
 7. The smoking article recited in claim 6 wherein theplug is generally cylindrical and the membrane is also in the form of acylinder laminated to said sidewall over the opening therein.
 8. Thesmoking article recited in claim 6 wherein the thickness of the membraneis less than about 0.01 inch and the distance between each of theorifices and the impingement surface is between about 0.008 and 0.022inch.
 9. The smoking article recited in claim 6 wherein the plugincludes a generally cylindrical forward section and a generallycylindrical rearward section of less radius than the former, wherein thesmoke passageway terminates in an opening in the sidewall of therearward section, and wherein a separate smoke-impervious sheetsupported by the forward section provides said impingement surface. 10.The smoking article recited in claim 9 wherein the rearward sectionincludes radially outwardly extending protuberances spaced rearwardly ofsaid orifices for further supporting the sheet providing the impingementsurface.